authors (intermediate)
Every WikiGroup can have GroupHeader and GroupFooter pages that contain markup that should be included at the beginning or end of each page within the group. This feature is useful for:

replacing the default headers and/or footers for pages in a group (e.g., using (:noheader:) and or (:nofooter:) -- see PageDirectives).

To create a group header, just create a new page called YourGroup.GroupHeader. Group headers allow authors to create groups with custom headers and footers without having to coordinate with a wiki administrator.

The default GroupHeader or GroupFooter can be suppressed on an individual page (such as a group's HomePage) by using the (:nogroupheader:) and (:nogroupfooter:) markups on that page.

If a generic GroupHeader is used in one wikigroup (say, the Site wikigroup), then the code can be easily duplicated in the GroupHeader of any other group by using
(:include Site.GroupHeader:). See IncludeOtherPages.

(note that single quotes must be used so that $Group (which is part of the default contents of $GroupHeaderFmt) will be substituted properly by PmWiki, and that this applies to all variables ending in $...Fmt)